Wire Gauge Calculator
Calculate wire diameter, cross-sectional area, and electrical resistance for AWG and SWG standards
Wire Gauge Properties Calculator
AWG is commonly used in North America, SWG in the UK
Lower numbers = thicker wire, higher numbers = thinner wire
Material affects electrical resistance calculation
Wire Properties
Wire Diameter
Cross-sectional Area
Electrical Resistance per Unit Length
Current Carrying Capacity
Approximate capacity for copper wire in free air at 30°C
Wire Specification: AWG 12 copper wire
Material Resistivity: 1.68e-8 Ω⋅m
Wire Gauge Analysis
Example Calculation - 12 AWG Copper Wire
Given Parameters
Wire Standard: AWG (American Wire Gauge)
Gauge Number: 12
Material: Copper
Copper Resistivity: 1.68 × 10⁻⁸ Ω⋅m
Calculations
Diameter: 0.005 × 92^((36-12)/39) = 0.0808 inches = 2.053 mm
Area: π × (0.0808/2)² = 0.00513 in² = 3.31 mm²
Resistance: 1.68×10⁻⁸ / (3.31×10⁻⁶) = 0.00508 Ω/m
Current Capacity: ~9.3 A (free air, 30°C)
Common AWG Wire Uses
Wire Safety Tips
Always use appropriately sized wire for the current load
Larger gauge numbers = thinner wire
Consider temperature derating factors
Follow local electrical codes
Consult a licensed electrician for installations
Understanding Wire Gauge Standards
American Wire Gauge (AWG)
AWG is a logarithmic stepped wire gauge system used primarily in North America since 1857. It's based on the diameter of solid, round, nonferrous electrical wire.
AWG Formula
diameter = 0.005 × 92^((36-n)/39) inches
- • Higher numbers = smaller diameter
- • Every 6 gauge decrease doubles diameter
- • Special cases: 0000, 000, 00, 0
- • Range: 0000 (largest) to 40+ (smallest)
Standard Wire Gauge (SWG)
SWG, also known as British Standard Wire Gauge, was historically used in the UK. It's based on the mil (0.001 inch) and uses a different numbering system.
Key Differences
- • Based on weight reduction per step (~20%)
- • Non-linear progression
- • Range: 7/0 (largest) to 50 (smallest)
- • Used for guitar strings and some electrical applications
Note: AWG and SWG use different formulas and aren't directly comparable
Electrical Resistance Calculation
The electrical resistance per unit length depends on the material's resistivity and the wire's cross-sectional area:
R/L = ρ / A
- R/L: Resistance per unit length (Ω/m)
- ρ: Material resistivity (Ω⋅m)
- A: Cross-sectional area (m²)